<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    header {
      background-color: pink;
      height: 100px;
    }
    main {
      height: 400px;
      background-color: green;
    }
    footer {
      height: 200px;
      background-color: blue;
    }
  </style>
</head>
<body>
  <!-- <span style="font-size: 20px;font-weight: 700;">我是span标签</span> -->
   <header>我是文章的标题，头部</header>
   <main>我是文章的主体内容</main>
   <footer>我是文章的底部内容</footer>
</body>
</html>